1. Field of the Invention
The present invention relates to an improved cyclone type dust collector without providing any rotation mechanism. The dust collector splashes dust existing in introduced raw air to an inner surface of a cylindrical air separating chamber by means of a centrifugal force generated by spiral airflow. Air remaining in the center of the air separating chamber is exhausted through a clean air exhaust duct.
2. Prior Art
FIG. 1 indicates a conventional cyclone type dust collector disclosed in the Japanese laid-open patent publication of 62-19269. Reference numeral 1 indicates a cyclone type dust collector. The dust collector comprises a cylinder 2a of a upper part and a reversed circular cone 2b of a lower part. Reference numeral 2 indicates an air separating chamber. A dust exhaust aperture 2c is disposed at lowest end of the reversed circular cone 2b. A clean air exhaust duct 3 whose lowest end is closed is provided coaxially passing through the air separating chamber 2 from the upper end of said air separating chamber 2. A notch of louver 3a is provided at a lower part of the clean air exhaust duct 3.
FIG. 2 indicates other conventional cyclone type dust collector disclosed in the Japanese laid-open patent publication of 62-19268. Reference numeral 4 indicates a cyclone type dust collector. The dust collector comprises a cylinder 5a of an upper part and a reversed circular cone 5b of a lower part. Reference numeral 5 indicates an air separating chamber. A dust exhaust aperture 5c is disposed at lowest end of the reversed circular cone 5b. A clean air exhaust duct 6 whose lowest end closed is provided coaxially passing through the air separating chamber 5 from the upper end of said air separating chamber 5. A net like filter 7 is provided at the lower part of said clean air exhaust duct 6.
Reference numeral 8 indicates an air intake duct provided in tangential direction at the cylinder 2a of the air separating chamber 2 in FIG. 1 or the cylinder 5a of the air separating chamber 5 in FIG. 2, respectively.
FIG. 3 and FIG. 4 indicate another conventional cyclone type dust collector disclosed in the Japanese patent publication of 6-91974. FIG. 3 shows a vertical cross section of the cyclone type dust collector. FIG. 4 indicates a horizontal cross section taken along the A--A line of FIG. 3.
In FIG. 3, reference numeral 11 indicates a cylindrical part connecting to an upper end of a reversed circular cone 12. A coarse particles expelling aperture 13 is disposed at lowest end of the reversed circular cone 12. A circular truncated cone 15 having a disc face 16 is disposed at lower axial center CL of the cylindrical part 11 in an air classifying chamber 14.
A divided airflow exhaust structure 18 and a spiral airflow intake structure 19 are disposed coaxially at an upper part 17 of the cylindrical part 11. The divided airflow exhaust structure 18 comprises an outer cylinder 20 of diameter d and an inner cylinder 21 of diameter 0.7 d, the latter is inserted into the former concentrically. Distance between the lowest end of the outer cylinder 20 and the disc face 16 of the circular truncated cone 15 is expressed with reference letter L. The distance between the lowest end of the inner cylinder 21 and the disc face of the circular truncated cone 15 is expressed with reference letter 1/2 L. The outer cylinder 20 and the inner cylinder 21 are connected to a suction apparatus (not shown in the figure) through an exhaust aperture 22.
Further in FIG. 4, the spiral airflow intake structure 19 is formed such that a dust laden raw air intake duct 25 is protruded in tangential direction from one side of a cylindrical air dividing chamber 24 formed outwardly and concentrically to an air dividing cylinder 23. The cylindrical air dividing chamber 24 is provided with a plural number of air dividing blades 26, 26 . . . protruded spirally and slantingly in inside diameter direction from an air dividing cylinder 23. A dust laden raw air intake duct is connected to said air dividing chamber 24. Raw air is supplied in a predetermined velocity of 12-20 m/s.
The above mentioned cyclone type dust collector intakes dust included raw air from the raw air intake duct 25. Coarse dust particles are expelled from a coarse particles expelling aperture 13 and fine dust particles are exhausted from a fine particles exhausting aperture 22.
According to the aforementioned cyclone type dust collector, the raw air introduced to the cylindrical air dividing chamber 24 through the intake duct 25 forms a spiral airflow as indicated by arrow a and are ejected to the air classifying chamber 14 by means of the air dividing blades 26, 26 . . . of the spiral airflow intake structure 19. The airflow gradually drops (toward dropping direction F1). While, as passages of exhaust air comprise the inner cylinder 21 and outer cylinder 22 and therefore air exhaust aperture is divided to two compartments, a centripetal force is generated toward center CL due to an even parallel airflows from the inner cylinder 21 and the outer cylinder 22 toward center CL. Due to the combination of the centrifugal force and the centripetal force the dust particles included in raw air drop toward composite direction expressed with reference letter F in FIG. 3.
The cyclone type dust collector shown in FIG. 1 is provided with notch of louver 3a. The particles larger than the notch of louver 3a is prevented from passing through said notch of louver. While, fine particles pass through said notch of louver are exhausted through the air exhaust duct 3.
The cyclone type dust collector shown in FIG. 2 has a defect that the filter is clogged and it must be replaced often with new one.
The cyclone type dust collector as shown in FIG. 3 and FIG. 4 has a plural number of air dividing blades 26, 26 . . . protruded under said cylindrical air dividing chamber 24 spirally and slantingly toward inside diameter direction from the inner surface of the air dividing cylinder 23. The air dividing blades 26, 26 . . . have a function to generate spiral airflow but they have no function to accelerate the spiral airflow.
The present invention has been made with the foregoing background in mind and its object resides in providing a dust collector which can eliminate fine dust. The dust collector has no net like filter. The dust collector has a function to accelerate the raw air coming into air separating chamber through cylindrical air dividing chamber. The accelerated air generates centrifugal force, thus dust laden raw air is gathered to the inner surface of the air dividing chamber and clean air remained in the center of the air dividing chamber is exhausted through the clean air exhaust duct.